1. Field of the Invention
This invention relates generally to material dispensing assemblies and more particularly to an assembly including an adjustable nozzle bar for dispensing a viscous material, such as an adhesive, onto a moving substrate in a variable pattern and frequency where the length, width and position of the pattern are readily adjustable with respect to the substrate and the nozzle bar is readily interchangeable with a nozzle bar having a different pattern.
2. Description of the Related Art
Nozzle assemblies are utilized to dispense a viscous adhesive onto containers, such as end flaps of cardboard boxes, prior to closing and filling the container with a desired material. An example of such an assembly is illustrated in pending U.S. application Ser. No. 07/962,666 which is assigned to the same assignee as the assignee herein. In that application, to vary the pattern of the adhesive applied, the nozzle assembly typically is removed and another nozzle assembly having the desired pattern is substituted.
Another way to vary the applied pattern is to provide a plurality of individual elongate nozzle outlets which in tandem comprise the entire pattern and then controlling each outlet with a separate dispensing solenoid valve. An example of such a device is illustrated in U.S. Pat. No. 4,687,137. That device, however, is not capable of varying the width of the pattern provided by the individual elongate nozzle outlets.
Additionally, U.S. Pat. No. 4,667,879 discloses a thermoplastic material applicator having an adjustable slot nozzle whose pattern is adjustable by rotation of a cylinder. The cylinder is mounted within the material flow path and, by rotating the cylinder, the width of the pattern can be adjusted about a center line of the slot nozzle.
Such an assembly, however, is not readily interchangeable to provide a different pattern of adhesive and is only capable of varying the width of the pattern about a center line of the slot nozzle. Accordingly, With that assembly it is not possible to position the pattern as desired across the slot nozzle, such as toward one end of the slot.
It therefore would be desirable to provide a material dispensing assembly having a nozzle bar which is readily interchangeable with another nozzle bar having a different pattern and is completely adjustable while mounted to the assembly to vary the length, width and position of the pattern anywhere across the nozzle bar and substrate to which the adhesive is applied.